Artificial intelligence improves resident detection of pediatric and young adult upper extremity fractures.

PURPOSE: We wished to evaluate if an open-source artificial intelligence (AI) algorithm ( https://www.childfx.com ) could improve performance of (1) subspecialized musculoskeletal radiologists, (2) radiology residents, and (3) pediatric residents in detecting pediatric and young adult upper extremity fractures. MATERIALS AND METHODS: A set of evaluation radiographs drawn from throughout the upper extremity (elbow, hand/finger, humerus/shoulder/clavicle, wrist/forearm, and clavicle) from 240 unique patients at a single hospital was constructed (mean age 11.3 years, range 0-22 years, 37.9% female). Two fellowship-trained musculoskeletal radiologists, three radiology residents, and two pediatric residents were recruited as readers. Each reader interpreted each case initially without and then subsequently 3-4 weeks later with AI assistance and recorded if/where fracture was present. RESULTS: Access to AI significantly improved area under the receiver operator curve (AUC) of radiology residents (0.768 [0.730-0.806] without AI to 0.876 [0.845-0.908] with AI, P < 0.001) and pediatric residents (0.706 [0.659-0.753] without AI to 0.844 [0.805-0.883] with AI, P < 0.001) in identifying fracture, respectively. There was no evidence of improvement for subspecialized musculoskeletal radiology attendings in identifying fracture (AUC 0.867 [0.832-0.902] to 0.890 [0.856-0.924], P = 0.093). There was no evidence of difference between overall resident AUC with AI and subspecialist AUC without AI (resident with AI 0.863, attending without AI AUC 0.867, P = 0.856). Overall physician radiograph interpretation time was significantly lower with AI (38.9 s with AI vs. 52.1 s without AI, P = 0.030). CONCLUSION: An openly accessible AI model significantly improved radiology and pediatric resident accuracy in detecting pediatric upper extremity fractures.

Complex Trauma Exposure and Placement Stability among Systems-Impacted Black and Latinx Youth: The Mediating Role of Multisystemic Strengths.

The purpose of this study is to investigate the mediating role of multisystemic strengths in the association between complex trauma (CT) exposure and placement stability among racialized youth using the Child and Adolescent Needs and Strength (CANS) assessment. Participants were 4022 Black and Latinx youth in the child welfare system in a midwestern state. Negative binomial regressions revealed a significant indirect effect of CT exposure on placement stability through interpersonal strengths (p < .01), coping skills (p < .001), optimism (p < .01), and talents/interests (p < .05). At the familial level, there was a significant indirect effect of CT exposure on placement stability through family strengths and relationship permanence (p < .001). At the community level, educational system supports, and community resources indirectly impacted the relationship between CT exposure and placement stability (p < .01). These findings suggest that early interventions aimed at identifying and developing multisystemic strengths in Black and Latinx youth in the child welfare system can help maximize placement stability.

New approaches build upon historical studies in dermal toxicology.

These are my personal reflections on the history of approaches to understanding dermal toxicology brought together for the Paton Prize Award. This is not a comprehensive account of all publications from in vivo studies in humans to development of in vitro and in silico approaches but highlghts important progress. I will consider what is needed now to influence approaches to understanding dermal exposure with the current development and use of NAMs (new approach methodologies).

Findings From the Step Up, Test Up Study of an Electronic Screening and Brief Intervention for Alcohol Misuse in Adolescents and Young Adults Presenting for HIV Testing: Randomized Controlled Efficacy Trial.

BACKGROUND: Substance use, particularly binge drinking of alcohol and noninjection substance use, is associated with increased risk for HIV infection among youth, but structured substance use screening and brief intervention are not often provided as part of HIV risk reduction. OBJECTIVE: The purpose of the study was to test the efficacy of a fully automated electronic screening and brief intervention, called Step Up, Test Up, to reduce alcohol misuse among adolescents and young adults presenting for HIV testing. Secondary objectives were reduction in sexual risk and uptake of pre-exposure prophylaxis (PrEP) for HIV prevention. METHODS: Youth aged 16 years to 25 years who presented for HIV testing at community-based locations were recruited for study participation. Those who screened at moderate to high risk on the Alcohol Use Disorders Identification Test were randomized (1:1) to either an electronic brief intervention or a time-attention control. The primary outcome was change in alcohol use at 1, 3, 6, and 12-month follow-ups. Negative binomial and log binomial regression analyses with generalized estimating equations were conducted to evaluate the intervention efficacy. RESULTS: Among a sample of 329 youth, there were no significant differences in alcohol use outcomes between conditions over time or at the 1, 3, 6, or 12-month time points. In terms of secondary outcomes, there was evidence of reduction in condomless insertive anal sex under the influence of alcohol and drugs at 12 months compared with 3 months in the intervention versus the attention control condition (incidence rate ratio=0.15, 95% CI 0.05-0.44); however, there were no other significant differences in sexual risk and no difference in PrEP engagement. CONCLUSIONS: We found no effect of electronic brief intervention to reduce alcohol use and some effect on sexual risk among youth aged 16 years to 25 years who present for HIV testing. TRIAL REGISTRATION: ClinicalTrials.gov number NCT02703116; https://clinicaltrials.gov/ct2/show/NCT02703116. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1186/s12889-020-8154-6.

A Scoping Review of Associations Between Cannabis Use and Anxiety in Adolescents and Young Adults.

Cannabis and anxiety are both rising issues that impact young people. This review seeks to explore the association between anxiety and cannabis in adolescents and young adults (AYA). A database search was run retrospectively from July 2020 through calendar year 2013. Articles had to present outcomes examining cannabis use and symptoms of anxiety, be written in English, contain samples with ≥ 50% who are age 25 or younger, and be published in a peer-reviewed journal. Forty-seven studies were identified that examined the relationship between anxiety and cannabis use. Twenty-three studies found a positive association that greater anxiety among AYA was associated with greater cannabis use. In contrast, seven studies found a negative association that greater anxiety was related to less cannabis use. And finally, 17 studies found no clear association between anxiety and cannabis use. Further research is needed to better understand the relationship between anxiety and cannabis use.

Universal masking to control healthcare-associated transmission of severe acute respiratory coronavirus virus 2 (SARS-CoV-2).

OBJECTIVES: To assess extent of a healthcare-associated outbreak of severe acute respiratory coronavirus virus 2 (SARS-CoV-2) and to evaluate the effectiveness of infection control measures, including universal masking. DESIGN: Outbreak investigation including 4 large-scale point-prevalence surveys. SETTING: Integrated VA healthcare system with 2 facilities and 330 beds. PARTICIPANTS: Index patient and 250 exposed patients and staff. METHODS: We identified exposed patients and staff and classified them as probable and confirmed cases based on symptoms and testing. We performed a field investigation and an assessment of patient and staff interactions to develop probable transmission routes. Infection prevention interventions included droplet and contact precautions, employee quarantine, and universal masking with medical and cloth face masks. We conducted 4 point-prevalence surveys of patient and staff subsets using real-time reverse-transcriptase polymerase chain reaction for SARS-CoV-2. RESULTS: Among 250 potentially exposed patients and staff, 14 confirmed cases of coronavirus disease 2019 (COVID-19) were identified. Patient roommates and staff with prolonged patient contact were most likely to be infected. The last potential date of transmission from staff to patient was day 22, the day universal masking was implemented. Subsequent point-prevalence surveys in 126 patients and 234 staff identified 0 patient cases and 5 staff cases of COVID-19, without evidence of healthcare-associated transmission. CONCLUSIONS: Universal masking with medical face masks was effective in preventing further spread of SARS-CoV-2 in our facility in conjunction with other traditional infection prevention measures.

A randomized controlled efficacy trial of an electronic screening and brief intervention for alcohol misuse in adolescents and young adults vulnerable to HIV infection: step up, test up study protocol.

BACKGROUND: Young people account for more than a quarter of new HIV infections in the US, with the majority of cases among young men who have sex with men; young transgender women are also vulnerable to infection. Substance use, particularly alcohol misuse, is a driver of sexual transmission and a potential barrier to engagement in the HIV prevention and care continuum, however vulnerable youth are difficult to reach for substance use services due, in part, to complex social and structural factors and limited access to health care. The Community Prevention Services Task Force recommends electronic screening and brief intervention as an evidence-based intervention for the prevention of excessive alcohol consumption; however, no prior studies have extended this model to community-based populations of youth that are susceptible to HIV infection. This paper describes the study protocol for an electronic screening and brief intervention to reduce alcohol misuse among adolescents and young adults vulnerable to HIV infection in community-based settings. METHODS: This study, Step Up, Test Up, is a randomized controlled trial of an electronic alcohol screening and brief intervention among youth, ages 16-25, who are vulnerable to HIV infection. Individuals who present for HIV testing at one of three community-based locations are recruited for study participation. Eligibility includes those aged 16-25 years, HIV-negative or unknown HIV status, male or trans female with a history of sex with men, and English-speaking. Participants who screen at moderate to high risk for alcohol misuse on the Alcohol Use Disorders Identification Test (AUDIT) are randomized (1:1) to either an electronic brief intervention to reduce alcohol misuse or a time-and attention-matched control. The primary outcome is change in the frequency/quantity of recent alcohol use at 1, 3, 6 and 12-month follow-up. DISCUSSION: Testing of evidence-based interventions to reduce alcohol misuse among youth vulnerable to HIV infection are needed. This study will provide evidence to determine feasibility and efficacy of a brief electronically-delivered intervention to reduce alcohol misuse for this population. TRIAL REGISTRATION: ClinicalTrials.gov number, NCT02703116, registered March 9, 2016.

A Longitudinally Extensive Spinal Cord Lesion Restricted to Gray Matter in an Adolescent Male.

Longitudinally extensive spinal cord lesions (LECL) restricted to gray matter are poorly understood as are their neurodevelopmental repercussions in children. We herein report the critical case of a 13-year-old male presenting with progressive quadriparesis found to have cervical LECL restricted to the anterior horns. Challenged with a rare diagnostic dilemma, the clinical team systematically worked through potential vascular, genetic, infectious, rheumatologic, and paraneoplastic diagnoses before assigning a working diagnosis of acute inflammatory myelopathy. Nuanced consideration of and workup for both potential ischemic causes (arterial dissection, fibrocartilaginous embolism, vascular malformation) and specific inflammatory conditions including Transverse Myelitis, Neuromyelitis Optica Spectrum Disorders (NMOSD), Multiple Sclerosis (MS), Acute Disseminated Encephalomyelitis (ADEM), and Acute Flaccid Myelitis (AFM) is explained in the context of a comprehensive systematic review of the literature on previous reports of gray matter-restricted longitudinally extensive cord lesions in children. Treatment strategy was ultimately based on additional literature review of treatment-refractory acute inflammatory neurological syndromes in children. A combination of high-dose steroids and plasmapheresis was employed with significant improvement in functional outcome, suggesting a potential benefit of combination immune-modulatory treatment in these patients. This case furthermore highlights quality clinical reasoning with respect to the elusive nature of diagnosis, nuances in neuroimaging, and multifocal treatment strategies in pediatric LECL.

DNA damage and repair proteins in cellular response to sulfur mustard in Iranian veterans more than two decades after exposure.

Delayed effects of sulfur mustard (SM) exposure on the levels of five important damage/repair proteins were investigated in 40 SM-exposed veterans of Iran-Iraq war and 35 unexposed controls. A major DNA damage biomarker protein - phosphorylated H2AX - along with four DNA repair proteins in cell response to the genome damage MRE11, NBS1, RAD51, and XPA were evaluated in blood lymphocytes from the veterans and controls using western blotting. Mean levels of XPA, MRE11, RAD51 and NBS1 were lower in SM-exposed patients and the decrease in NBS1 was significant. Even though the raised level of phosphor-H2AX in SM-poisoned group compared to the controls was not significant it was consistent with DNA damage findings confirming the severity of damage to the DNA after exposure to SM. There were correlations between the values of RAD51 and NBS1 proteins as well as XPA and MRE11 proteins. More than two decades after exposure to SM, there is still evidences of DNA damage as well as impaired repair mechanisms in cells of exposed individuals. Such disorders in cellular level may contribute to long term health problems of the SM veterans.

Intestinal parasites from the 2nd-5th century AD latrine in the Roman Baths at Sagalassos (Turkey).

The aim of this research was to determine the species of intestinal parasite present in a Roman Imperial period population in Asia Minor, and to use this information to improve our understanding of health in the eastern Mediterranean region in Roman times. We analyzed five samples from the latrines of the Roman bath complex at Sagalassos, Turkey. Fecal biomarker analysis using 5ß-stanols has indicated the feces were of human origin. The eggs of roundworm (Ascaris) were identified in all five samples using microscopy, and the cysts of the protozoan Giardia duodenalis (which causes dysentery) were identified multiple times in one sample using ELISA. The positive G. duodenalis result at Sagalassos is particularly important as it represents the earliest reliable evidence for this parasite in the Old World (i.e. outside the Americas). As both these species of parasite are spread through the contamination of food and water by fecal material, their presence implies that Roman sanitation technologies such as latrines and public baths did not break the cycle of reinfection in this population. We then discuss the evidence for roundworm in the writings of the Roman physician Galen, who came from Pergamon, another town in western Asia Minor.

Hepatic effects of tartrazine (E 102) after systemic exposure are independent of oestrogen receptor interactions in the mouse.

Tartrazine is a food colour that activates the transcriptional function of the human oestrogen receptor alpha in an in vitro cell model. Since oestrogens are cholestatic, we hypothesised tartrazine will cause periportal injury to the liver in vivo. To test this hypothesis, tartrazine was initially administered systemically to mice resulting in a periportal recruitment of inflammatory cells, increased serum alkaline phosphatase activity and mild periportal fibrosis. To determine whether an oestrogenic effect may be a key event in this response, tartrazine, sulphonated metabolites and a food additive contaminant were screened for their ability to interact with murine oestrogen receptors. In all cases, there were no interactions as agonists or antagonists and further, no oestrogenicity was observed with tartrazine in an in vivo uterine growth assay. To examine the relevance of the hepatic effects of tartrazine to its use as a food additive, tartrazine was orally administered to transgenic NF-κB-Luc mice. Pre- and concurrent oral treatment with alcohol was incorporated given its potential to promote gut permeability and hepatic inflammation. Tartrazine alone induced NF- κB activities in the colon and liver but there was no periportal recruitment of inflammatory cells or fibrosis. Tartrazine, its sulphonated metabolites and the contaminant inhibited sulphotransferase activities in murine hepatic S9 extracts. Given the role of sulfotransferases in bile acid excretion, the initiating event giving rise to periportal inflammation and subsequent hepatic pathology through systemic tartrazine exposure is therefore potentially associated an inhibition of bile acid sulphation and excretion and not on oestrogen receptor-mediated transcriptional function. However, these effects were restricted to systemic exposures to tartrazine and did not occur to any significant effect after oral exposure.

Assessing the safety of cosmetic chemicals: Consideration of a flux decision tree to predict dermally delivered systemic dose for comparison with oral TTC (Threshold of Toxicological Concern).

Threshold of Toxicological Concern (TTC) aids assessment of human health risks from exposure to low levels of chemicals when toxicity data are limited. The objective here was to explore the potential refinement of exposure for applying the oral TTC to chemicals found in cosmetic products, for which there are limited dermal absorption data. A decision tree was constructed to estimate the dermally absorbed amount of chemical, based on typical skin exposure scenarios. Dermal absorption was calculated using an established predictive algorithm to derive the maximum skin flux adjusted to the actual 'dose' applied. The predicted systemic availability (assuming no local metabolism), can then be ranked against the oral TTC for the relevant structural class. The predictive approach has been evaluated by deriving the experimental/prediction ratio for systemic availability for 22 cosmetic chemical exposure scenarios. These emphasise that estimation of skin penetration may be challenging for penetration enhancing formulations, short application times with incomplete rinse-off, or significant metabolism. While there were a few exceptions, the experiment-to-prediction ratios mostly fell within a factor of 10 of the ideal value of 1. It can be concluded therefore, that the approach is fit-for-purpose when used as a screening and prioritisation tool.

Characterization of multidrug transporter-mediated efflux of avermectins in human and mouse neuroblastoma cell lines.

ABC transporters play an important role in the disposition of avermectins in several animal species. In this study the interactions of three key avermectins, abamectin, emamectin and ivermectin, with human and mouse homologues of MDR1 (ABCB1/Abcb1a) and MRP (ABCC/Abcc), transporters endogenously expressed by human SH-SY5Y and mouse N2a neuroblastoma cells were investigated. In both cell lines, retention of the fluorescent dye H33342 was found to be significantly increased in the presence of avermectins and cyclosporin A. These effects were shown to be unresponsive to the BCRP inhibitor Ko-143 and therefore MDR1/Mdr1-dependent. Avermectins inhibited MDR1/Mdr1a-mediated H33342 dye efflux, with apparent Ki values of 0.24±0.08 and 0.18±0.02µM (ivermectin); 0.60±0.07 and 0.56±0.02µM (emamectin) and 0.95±0.08 and 0.77±0.25µM (abamectin) in SH-SY5Y and N2a cells, respectively. There were some apparent affinity differences for MDR1 and Mdr1a within each cell line (affinity for ivermectin>emamectin≥abamectin, P<0.05 by One-Way ANOVA), but importantly, the Ki values for individual avermectins for human MDR1 or mouse Mdr1a were not significantly different. MK571-sensitive retention of GSMF confirmed the expression of MRP/Mrp efflux transporters in both cell lines. Avermectins inhibited MRP/Mrp-mediated dye efflux with IC50 values of 1.58±0.51 and 1.94±0.72µM (ivermectin); 1.87±0.57 and 2.74±1.01µM (emamectin) and 2.25±0.01 and 1.68±0.63µM (abamectin) in SH-SY5Y and N2a cells, respectively. There were no significant differences in IC50 values between individual avermectins or between human MRP and mouse Mrp. Kinetic data for endogenous human MDR1/MRP isoforms in SH-SY5Y cells and mouse Mdr1a/b/Mrp isoforms in N2a cells are comparable for the selected avermectins. All are effluxed at concentrations well above 0.05-0.1µM ivermectin detected in plasma (Ottesen and Campbell, 1994; Ottesen and Campbell, 1994) This is an important finding in the light of toxicity seen in the Mdr1-deficient animal models CF-1 mice, Mdr1ab (-/-) double knockout mice and Collie dogs. We also confirm MRP/Mrp-mediated avermectin transport in both N2a and SH-SY5Y cell lines.

Induction of a chloracne phenotype in an epidermal equivalent model by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is dependent on aryl hydrocarbon receptor activation and is not reproduced by aryl hydrocarbon receptor knock down.

BACKGROUND: 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent activator of the aryl hydrocarbon receptor (AhR) and causes chloracne in humans. The pathogenesis and role of AhR in chloracne remains incompletely understood. OBJECTIVE: To elucidate the mechanisms contributing to the development of the chloracne-like phenotype in a human epidermal equivalent model and identify potential biomarkers. METHODS: Using primary normal human epidermal keratinocytes (NHEK), we studied AhR activation by XRE-luciferase, AhR degradation and CYP1A1 induction. We treated epidermal equivalents with high affinity TCDD or two non-chloracnegens: ß-naphthoflavone (ß-NF) and 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE). Using Western blotting and immunochemistry for filaggrin (FLG), involucrin (INV) and transglutaminase-1 (TGM-1), we compared the effects of the ligands on keratinocyte differentiation and development of the chloracne-like phenotype by H&E. RESULTS: In NHEKs, activation of an XRE-luciferase and CYP1A1 protein induction correlated with ligand binding affinity: TCDD>ß-NF>ITE. AhR degradation was induced by all ligands. In epidermal equivalents, TCDD induced a chloracne-like phenotype, whereas ß-NF or ITE did not. All three ligands induced involucrin and TGM-1 protein expression in epidermal equivalents whereas FLG protein expression decreased following treatment with TCDD and ß-NF. Inhibition of AhR by α-NF blocked TCDD-induced AhR activation in NHEKs and blocked phenotypic changes in epidermal equivalents; however, AhR knock down did not reproduce the phenotype. CONCLUSION: Ligand-induced CYP1A1 and AhR degradation did not correlate with their chloracnegenic potential, indicating that neither CYP1A1 nor AhR are suitable biomarkers. Mechanistic studies showed that the TCDD-induced chloracne-like phenotype depends on AhR activation whereas AhR knock down did not appear sufficient to induce the phenotype.

Tartrazine and sunset yellow are xenoestrogens in a new screening assay to identify modulators of human oestrogen receptor transcriptional activity.

Primary biliary cirrhosis (PBC) is a cholestatic liver disease of unknown cause that occurs most frequently in post-menopausal women. Since the female sex hormone oestrogen can be cholestatic, we hypothesised that PBC may be triggered in part by chronic exposure to xenoestrogens (which may be more active on a background of low endogenous oestrogen levels seen in post-menopausal women). A reporter gene construct employing a synthetic oestrogen response element predicted to specifically interact with oestrogen receptors (ER) was constructed. Co-transfection of this reporter into an ER null cell line with a variety of nuclear receptor expression constructs indicated that the reporter gene was trans-activated by ERα and ERß, but not by the androgen, thyroid, progesterone, glucocorticoid or vitamin D receptors. Chemicals linked to PBC were then screened for xenoestrogen activity in the human ERα-positive MCF-7 breast cancer cell line. Using this assay, the coal-derived food and cosmetic colourings--sunset yellow and tartrazine--were identified as novel human ERα activators, activating the human ER with an EC(50%) concentration of 220 and 160 nM, respectively.

DNA damage responses in cells exposed to sulphur mustard.

Sulphur mustard (SM) is a blistering agent that causes debilitating damage to the skin, eyes and respiratory system. In cases of severe exposure, immunodepletion can occur as well as death, due to secondary infections. The toxicity of SM is thought to be mediated in part by the alkylation of nucleic acids and proteins, although the exact mechanisms are not clear. In addition, although the first known use of SM was in military conflict nearly 100 years ago, there are still no effective treatments or preventative measures. In order to develop treatments it is necessary to have a detailed understanding of the cellular biochemical changes induced by SM as well as information on the mechanisms that cells employ to protect against SM toxicity. We have previously demonstrated that the homologous recombination (HR) DNA repair pathway promotes cell survival after SM. This study investigated the role of other DNA repair pathways in the cellular response to SM, specifically base excision repair (BER), nucleotide excision repair (NER) and non-homologous end joining (NHEJ) as well as studying the activation and regulation of DNA damage signalling pathways. Our data confirmed that HR is the major repair pathway protecting against acute SM toxicity, with NER and NHEJ also contributing to cell survival. In addition, this study demonstrated the dose- and time-dependent activation of DNA damage signalling pathways after SM in human TK6 lymphoblastoid cells, in particular the phosphorylation of CHK1, CHK2 and p53. These phosphorylation events were orchestrated by a combination of the ATM and ATR protein kinases.

The role of homologous recombination in the cellular response to sulphur mustard.

Sulphur mustard (SM) is a blistering agent that has been used several times as a weapon during military conflict. Interest in this compound persists due to its ease of production and potential threat as an agent of warfare/terrorism. In addition, there are increasing reports of long-term health effects in individuals previously exposed to this compound, including an increased incidence of certain cancers. It is therefore important to elucidate the toxic mechanisms of SM and how the cell responds to any damage produced. This will allow for better healthcare planning in the event of an exposure and aid in the development of a therapeutic strategy, which is currently lacking. SM is a bifunctional alkylating agent, producing both DNA monoadducts and crosslinks, although the cellular response to these lesions is not well understood. This study aimed to investigate the DNA repair pathways employed by cells exposed to SM. It was found that DNA double strand breaks were generated after SM exposure and cells lacking the homologous recombination DNA repair pathway were more sensitive to the toxicity of SM than wild type cells. Finally, we demonstrate that chemical activation of the HR protein RAD51 offers cellular protection against SM toxicity and thus could be a novel target for therapeutic intervention.

The 2008 ICOH Workshop on Skin Notation.

BACKGROUND: On 29 March 2008 the International Commission on Occupational Health (ICOH) Scientific Committee on Occupational and Environmental Dermatoses organized a Skin Notation Workshop hosted by the 11th International Percutaneous Penetration Perspectives Conference (La Grande Motte, France). Skin notation (S) was chosen as a topic for discussion because this is the only example of existing regulation in the field of dermal risk assessment. The issue was discussed in a previous workshop held in Siena, Italy in 2006 with the objective of focussing on the problems related to S, the different assignment criteria and the attempts to improve the S system made by various international and governmental agencies. A position paper was subsequently published. OBJECTIVES: The workshop in France was a continuation of this activity with the aim of evaluating how the different strategies can improve S. METHODS AND DISCUSSION: The Workshop was divided into two sessions. The first was dedicated to lectures focused on different aspects of S. In the second session participants discussed key issues with the aim of exploring the actions needed to improve international S. systems.

Genotoxic effect induced by hydrogen peroxide in human hepatoma cells using comet assay.

BACKGROUND: Hydrogen peroxide (H(2)O(2)) is a common reactive oxygen intermediate generated by various forms of oxidative stress. AIM: The aim of this study was to investigate the DNA damage capacity of H(2)O(2) in HepG2 cells. METHODS: Cells were treated with H(2)O(2) at concentrations of 25 µM or 50 µM for 5 min, 30 min, 40 min, 1 h, or 24 h in parallel. The extent of DNA damage was assessed by the comet assay. RESULTS: Compared to the control, DNA damage by 25 and 50 µM H(2)O(2) increased significantly with increasing incubation time up to 1 h, but it was not increased at 24 h. CONCLUSIONS: Our findings confirm that H(2)O(2) is a typical DNA damage-inducing agent and thus is a good model system to study the effects of oxidative stress. DNA damage in HepG2 cells increased significantly with H(2)O(2) concentration and time of incubation but later decreased likely due to DNA repair mechanisms and antioxidant enzymes.